Computer -aided prediction of the launching behaviour of a free-fall lifeboat

Abstract

Free-fall lifeboats have become a common lifesaving appliance on ships and offshore facilities. The manner of launching a free-fall lifeboat makes it difficult to predict its behaviour and poses the potential risk of injury to its occupants. This paper is focused on determining the trajectory of the lifeboat and dynamic forces acting upon its occupants, with the aim of minimizing the risk of injury. The proposed approach is based on the computer simulation combined in a rational way with model tests, as well as measurements carried out on prototypes. The algorithm and software package has been developed for prediction of the free-fall lifeboat launching behaviour. The simulation procedure, when used in the process of design, allows for improvement to the hull shape, to determine proper position and shaping of seats so as to ensure minimum load is exerted upon the lifeboat occupants. Acceleration measurements were carried out whilst launching a model and an original boat, as well as observations on the ability of the boat to make positive headway. Results of the simulation and measurement were compared. The proposed approach to the problem meant an efficient design aid was produced, leading to the introduction of substantial changes in a series of free-fall lifeboats, aimed at improving safety of its occupants.